publications

2025

1. Evaluating Continuous Queries with Inconsistency Annotations

   Samuele Langhi, Angela Bonifati, and Riccardo Tommasini

   Proc. VLDB Endow., 2025
2. Towards Hybrid Graphs: Unifying Property Graphs and Time Series

   Mouna Ammar, Christopher Rost, Riccardo Tommasini , and 5 more authors

   In Proceedings 28th International Conference on Extending Database Technology, EDBT 2025, Barcelona, Spain, March 25-28, 2025 , 2025
3. Back to the Order: Partial orders in streaming conformance checking

   Kristo Raun, Riccardo Tommasini, and Ahmed Awad

   Information Systems, 2025

   Abs

   Most organizations are built around their business processes. Commonly, these processes follow a predefined path. Deviations from the expected path can lead to lower quality products and services, reduced efficiencies, and compliance liabilities. Rapid identification of deviations helps mitigate such risks. For identifying deviations, the conformance checker would need to know the sequence in which events occurred. In this paper, we tackle two challenges associated with knowing the right sequence of events. First, we look at out-of-order event arrival, a common occurrence in modern information systems. Second, we extend the previous work by incorporating partial order handling. Partially ordered events are a well-studied problem in process mining, but to the best of our knowledge it has not been researched in terms of fast-paced streaming conformance checking. Real-life and semi-synthetic datasets are used for validating the proposed methods.

4. No Rule is Forever: Datalog Reasoning with Rule Amendments

   Weiqin Xu, Riccardo Tommasini, and Olivier Curé

   In 2025 IEEE 41st International Conference on Data Engineering (ICDE) , May 2025

   Abs

   Datalog has grown in popularity with its integration into various commercial and open-source systems. One significant application of Datalog is in stream reasoning scenarios, particularly in the context of Internet of Things and Edge Computing, where it supports the derivation of implicit consequences from incomplete streaming data. The dynamic nature of edge infrastructure, with constantly changing data and deduction rules, poses additional challenges for incremental reasoning. This paper introduces Zodiac, a method for reasoning under rule amendments, and ZodiacEdge, a system implementing this method. Zodiac is based on Datalog stratification and semi-naive evaluation but includes a novel data structure that supports incremental maintenance of deductions for fast rule amendments, even in the presence of negation and aggregation. ZodiacEdge is designed to work with RDF data, accepting Datalog programs with predicates of a maximum arity of two.

2024

1. A holistic view over ontologies for Streaming Linked Data

   Pieter Bonte, Femke Ongenae, and Riccardo Tommasini

   Semantic Web, May 2024

   Abs

   Streaming Linked Data represents a domain within the Semantic Web dedicated to incorporating Stream Reasoning capabilities into the Semantic Web stack to address dynamic data challenges. Such applied endeavours typically necessitate a robust data modelling process. To this end, RDF Stream Processing (RSP) engines frequently utilize OWL 2 ontologies to facilitate this requirement. Despite the rich body of research on Knowledge Representation (KR), even concerning time-sensitive data, a notable gap exists in the literature regarding a comprehensive survey on KR techniques tailored for Streaming Linked Data. This paper critically overviews the key ontologies employed in RSP applications, evaluating their data modelling and KR abilities specifically for Streaming Linked Data contexts. We analyze these ontologies through three distinct KR perspectives: the conceptualization of streams as Web resources, the structural organization of data streams, and the event modelling within the streams. An analytical framework is introduced for each perspective to ensure a thorough and equitable comparison and deepen the understanding of the surveyed ontologies.

2. GenACT: An Ontology-Based Temporal Web Data Generator

   Gunjan Singh, Udit Arora, Shashikant Kumar , and 4 more authors

   In Conceptual Modeling - 43rd International Conference, ER 2024, Pittsburgh, PA, USA, October 28-31, 2024, Proceedings , May 2024
3. TGDK

   Grounding Stream Reasoning Research

   Pieter Bonte, Jean-Paul Calbimonte, Daniel Leng , and 12 more authors

   TGDK, May 2024
4. DOLAP

   Adaptive Handling of Out-of-order Streams in Conformance Checking

   Kristo Raun, Riccardo Tommasini, and Ahmed Awad

   In Proceedings of the 26th International Workshop on Design, Optimization, Languages and Analytical Processing of Big Data (DOLAP 2024) co-located with the 27th International Conference on Extending Database Technology and the 27th International Conference on Database Theory (EDBT/ICDT 2024), Paestum, Italy, March 25, 2024 , May 2024

   Awarded

   Best Paper

5. EDBT

   Seraph: Continuous Queries on Property Graph Streams

   Christopher Rost, Riccardo Tommasini, Angela Bonifati , and 6 more authors

   In Proceedings 27th International Conference on Extending Database Technology, EDBT 2024, Paestum, Italy, March 25 - March 28 , May 2024
6. Towards Streaming Consistency Management

   Samuele Langhi, Angela Bonifati, and Riccardo Tommasini

   In 40th IEEE International Conference on Data Engineering, ICDE 2024, Utrecht, The Netherlands, May 13-16, 2024 , May 2024
7. Property Graph Stream Processing In Action with Seraph

   Riccardo Tommasini, Christopher Rost, Angela Bonifati , and 6 more authors

   In Companion of the 2024 International Conference on Management of Data, SIGMOD/PODS 2024, Santiago AA, Chile, June 9-15, 2024 , May 2024
8. An Overview of Continuous Querying in (Modern) Data Systems

   Angela Bonifati, and Riccardo Tommasini

   In Companion of the 2024 International Conference on Management of Data, SIGMOD/PODS 2024, Santiago AA, Chile, June 9-15, 2024 , May 2024

2023

1. TGDK

   How Does Knowledge Evolve in Open Knowledge Graphs?

   Axel Polleres, Romana Pernisch, Angela Bonifati , and 11 more authors

   TGDK, May 2023
2. Streaming linked data: A survey on life cycle compliance

   Pieter Bonte, and Riccardo Tommasini

   J. Web Semant., May 2023
3. DEBS

   I Will Survive: An Event-driven Conformance Checking Approach Over Process Streams

   Kristo Raun, Riccardo Tommasini, and Ahmed Awad

   In Proceedings of the 17th ACM International Conference on Distributed and Event-based Systems, DEBS 2023, Neuchatel, Switzerland, June 27-30, 2023 , May 2023

   Awarded

   Best Paper

4. Big Data Analytics from the Rich Cloud to the Frugal Edge

   Feras M. Awaysheh, Riccardo Tommasini, and Ahmed Awad

   In IEEE International Conference on Edge Computing and Communications, EDGE 2023, Chicago, IL, USA, July 2-8, 2023 , May 2023
5. ESWC

   IMKG: The Internet Meme Knowledge Graph

   Riccardo Tommasini, Filip Ilievski, and Thilini Wijesiriwardene

   In The Semantic Web - 20th International Conference, ESWC 2023, Hersonissos, Crete, Greece, May 28 - June 1, 2023, Proceedings , May 2023
6. Explainable Classification of Internet Memes

   Abhinav Kumar Thakur, Filip Ilievski, Hông-Ân Sandlin , and 4 more authors

   In Proceedings of the 17th International Workshop on Neural-Symbolic Learning and Reasoning, La Certosa di Pontignano, Siena, Italy, July 3-5, 2023 , May 2023

2022

1. D2IA: User-defined interval analytics on distributed streams

   Ahmed Awad, Riccardo Tommasini, Samuele Langhi , and 3 more authors

   Inf. Syst., May 2022
2. PAPyA: Performance Analysis of Large RDF Graphs Processing Made Easy

   Mohamed Ragab, Adam Satria Adidarma, and Riccardo Tommasini

   CoRR, May 2022
3. Multimodal and Explainable Internet Meme Classification

   Abhinav Kumar Thakur, Filip Ilievski, Hông-Ân Sandlin , and 4 more authors

   CoRR, May 2022

2021

1. CACM

   The future is big graphs: a community view on graph processing systems

   Sherif Sakr, Angela Bonifati, Hannes Voigt , and 38 more authors

   Commun. ACM, May 2021

   Awarded

   Cover Work

2. ESWC

   RSP4J: An API for RDF Stream Processing

   Riccardo Tommasini, Pieter Bonte, Femke Ongenae , and 1 more author

   In The Semantic Web - 18th International Conference, ESWC 2021, Virtual Event, June 6-10, 2021, Proceedings , May 2021

   Awarded

   Best Resource

2020

1. Extending Kafka Streams for Complex Event Recognition

   Samuele Langhi, Riccardo Tommasini, and Emanuele Della Valle

   In IEEE International Conference on Big Data, Big Data 2020, Atlanta, GA, USA, December 10-13, 2020 , May 2020
2. Towards making sense of Spark-SQL performance for processing vast distributed RDF datasets

   Mohamed Ragab, Riccardo Tommasini, Sadiq Eyvazov , and 1 more author

   In Proceedings of The International Workshop on Semantic Big Data, SBD@SIGMOD 2020, Portland, Oregon, USA, June 19, 2020 , May 2020
3. ICWE

   On Teaching Web Stream Processing - Lessons Learned

   Riccardo Tommasini, Emanuele Della Valle, Marco Balduini , and 1 more author

   In Web Engineering - 20th International Conference, ICWE 2020, Helsinki, Finland, June 9-12, 2020, Proceedings , May 2020
4. Declarative Languages for Big Streaming Data

   Riccardo Tommasini, Sherif Sakr, Emanuele Della Valle , and 1 more author

   In Proceedings of the 23rd International Conference on Extending Database Technology, EDBT 2020, Copenhagen, Denmark, March 30 - April 02, 2020 , May 2020
5. The Kaiju project: enabling event-driven observability

   Mario Scrocca, Riccardo Tommasini, Alessandro Margara , and 2 more authors

   In DEBS ’20: The 14th ACM International Conference on Distributed and Event-based Systems, Montreal, Quebec, Canada, July 13-17, 2020 , May 2020
6. ISWC

   A First Step Towards a Streaming Linked Data Life-Cycle

   Riccardo Tommasini, Mohamed Ragab, Alessandro Falcetta , and 2 more authors

   In The Semantic Web - ISWC 2020 - 19th International Semantic Web Conference, Athens, Greece, November 2-6, 2020, Proceedings, Part II , May 2020

2019

1. AAMAS

   Stream Reasoning Agents: Blue Sky Ideas Track

   Riccardo Tommasini, Davide Calvaresi, and Jean-Paul Calbimonte

   In Proceedings of the 18th International Conference on Autonomous Agents and MultiAgent Systems, AAMAS ’19, Montreal, QC, Canada, May 13-17, 2019 , May 2019
2. CAISE

   D2IA: Stream Analytics on User-Defined Event Intervals

   Ahmed Awad, Riccardo Tommasini, Mahmoud Kamel , and 2 more authors

   In Advanced Information Systems Engineering - 31st International Conference, CAiSE 2019, Rome, Italy, June 3-7, 2019, Proceedings , May 2019

   Awarded

   Best Paper

3. C-Sprite: Efficient Hierarchical Reasoning for Rapid RDF Stream Processing

   Pieter Bonte, Riccardo Tommasini, Filip De Turck , and 2 more authors

   In Proceedings of the 13th ACM International Conference on Distributed and Event-based Systems, DEBS 2019, Darmstadt, Germany, June 24-28, 2019. , May 2019
4. EDBT

   An Outlook to Declarative Languages for Big Streaming Data

   Riccardo Tommasini, Sherif Sakr, Marco Balduini , and 1 more author

   In Proceedings of the 13th ACM International Conference on Distributed and Event-based Systems, DEBS 2019, Darmstadt, Germany, June 24-28, 2019. , May 2019
5. Velocity on the Web - a PhD Symposium

   Riccardo Tommasini

   In Companion of The 2019 World Wide Web Conference, WWW 2019, San Francisco, CA, USA, May 13-17, 2019. , May 2019
6. Continuous Analytics of Web Streams

   Riccardo Tommasini, Robin Keskisärkkä, Jean-Paul Calbimonte , and 3 more authors

   In Companion of The 2019 World Wide Web Conference, WWW 2019, San Francisco, CA, USA, May 13-17, 2019. , May 2019

2018

1. Streaming MASSIF: Cascading Reasoning for Efficient Processing of IoT Data Streams

   Pieter Bonte, Riccardo Tommasini, Emanuele Della Valle , and 2 more authors

   Sensors, May 2018
2. A Query Model for Ontology-Based Event Processing over RDF Streams

   Riccardo Tommasini, Pieter Bonte, Emanuele Della Valle , and 2 more authors

   In Knowledge Engineering and Knowledge Management - 21st International Conference, EKAW 2018, Nancy, France, November 12-16, 2018, Proceedings , May 2018
3. On the Semantics of Tpf-qs towards Publishing and Querying rdf Streams at Web-scale

   Ruben Taelman, Riccardo Tommasini, Joachim Van Herwegen , and 3 more authors

   In Proceedings of the 14th International Conference on Semantic Systems, SEMANTICS 2018, Vienna, Austria, September 10-13, 2018 , May 2018
4. Engineering of Web Stream Processing Applications

   Emanuele Della Valle, Riccardo Tommasini, and Marco Balduini

   In Reasoning Web. Learning, Uncertainty, Streaming, and Scalability - 14th International Summer School 2018, Esch-sur-Alzette, Luxembourg, September 22-26, 2018, Tutorial Lectures , May 2018
5. VoCaLS: Describing Streams on the Web

   Riccardo Tommasini, Yehia Abo Sedira, Daniele Dell’Aglio , and 5 more authors

   In Proceedings of the ISWC 2018 Posters & Demonstrations, Industry and Blue Sky Ideas Tracks co-located with 17th International Semantic Web Conference (ISWC 2018), Monterey, USA, October 8th - to - 12th, 2018. , May 2018

   Awarded

   Best Poster

6. L’Inking You To A Knowledge Graph

   Riccardo Tommasini, and Emanuele Della Valle

   In Proceedings of the ISWC 2018 Posters & Demonstrations, Industry and Blue Sky Ideas Tracks co-located with 17th International Semantic Web Conference (ISWC 2018), Monterey, USA, October 8th - to - 12th, 2018. , May 2018
7. VoCaLS: Vocabulary and Catalog of Linked Streams

   Riccardo Tommasini, Yehia Abo Sedira, Daniele Dell’Aglio , and 5 more authors

   In The Semantic Web - ISWC 2018 - 17th International Semantic Web Conference, Monterey, CA, USA, October 8-12, 2018, Proceedings, Part II , May 2018

2017

1. Defining the execution semantics of stream processing engines

   Lorenzo Affetti, Riccardo Tommasini, Alessandro Margara , and 2 more authors

   J. Big Data, May 2017
2. ESWC

   SLD Revolution: A Cheaper, Faster yet more Accurate Streaming Linked Data Framework

   Marco Balduini, Emanuele Della Valle, and Riccardo Tommasini

   In Joint Proceedings of the 2nd RDF Stream Processing (RSP 2017) and the Querying the Web of Data (QuWeDa 2017) Workshops co-located with 14th ESWC 2017 (ESWC 2017), Portoroz, Slovenia, May 28th - to - 29th, 2017. , May 2017
3. ESWC

   Towards a Benchmark for Expressive Stream Reasoning

   Riccardo Tommasini, Marco Balduini, and Emanuele Della Valle

   In Joint Proceedings of the 2nd RDF Stream Processing (RSP 2017) and the Querying the Web of Data (QuWeDa 2017) Workshops co-located with 14th ESWC 2017 (ESWC 2017), Portoroz, Slovenia, May 28th - to - 29th, 2017. , May 2017
4. ESWC

   SLD Revolution: A Cheaper, Faster yet More Accurate Streaming Linked Data Framework

   Marco Balduini, Emanuele Della Valle, and Riccardo Tommasini

   In The Semantic Web: ESWC 2017 Satellite Events - ESWC 2017 Satellite Events, Portorož, Slovenia, May 28 - June 1, 2017, Revised Selected Papers , May 2017
5. ISWC

   Stressless RSP Benchmarking With RSPLab

   Andrea Mauri, Riccardo Tommasini, Emanuele Della Valle , and 1 more author

   In Proceedings of the ISWC 2017 Posters & Demonstrations and Industry Tracks co-located with 16th International Semantic Web Conference (ISWC 2017), Vienna, Austria, October 23rd - to - 25th, 2017. , May 2017
6. ISWC

   Representing Dockerfiles in RDF

   Riccardo Tommasini, Ben De Meester, Pieter Heyvaert , and 3 more authors

   In Proceedings of the ISWC 2017 Posters & Demonstrations and Industry Tracks co-located with 16th International Semantic Web Conference (ISWC 2017), Vienna, Austria, October 23rd - to - 25th, 2017. , May 2017
7. Challenges & Opportunities of RSP-QL Implementations

   Riccardo Tommasini, and Emanuele Della Valle

   In Joint Proceedings of the Web Stream Processing workshop (WSP 2017) and the 2nd International Workshop on Ontology Modularity, Contextuality, and Evolution (WOMoCoE 2017) co-located with 16th International Semantic Web Conference (ISWC 2017), Vienna, Austria, October 22nd, 2017. , May 2017
8. Yasper 1.0: Towards an RSP-QL Engine

   Riccardo Tommasini, and Emanuele Della Valle

   In Proceedings of the ISWC 2017 Posters & Demonstrations and Industry Tracks co-located with 16th International Semantic Web Conference (ISWC 2017), Vienna, Austria, October 23rd - to - 25th, 2017. , May 2017
9. Towards VoIS: A Vocabulary of Interlinked Streams

   Yehia Abo Sedira, Riccardo Tommasini, and Emanuele Della Valle

   In Proceedings of the Workshop on Decentralizing the Semantic Web 2017 co-located with 16th International Semantic Web Conference (ISWC 2017) , May 2017
10. MobileWave: Publishing RDF Streams From SmartPhones

    Yehia Abo Sedira, Riccardo Tommasini, and Emanuele Della Valle

    In Proceedings of the ISWC 2017 Posters & Demonstrations and Industry Tracks co-located with 16th International Semantic Web Conference (ISWC 2017), Vienna, Austria, October 23rd - to - 25th, 2017. , May 2017
11. RSPLab: RDF Stream Processing Benchmarking Made Easy

    Riccardo Tommasini, Emanuele Della Valle, Andrea Mauri , and 1 more author

    In The Semantic Web - ISWC 2017 - 16th International Semantic Web Conference, Vienna, Austria, October 21-25, 2017, Proceedings, Part II , May 2017

2016

1. Heaven: A Framework for Systematic Comparative Research Approach for RSP Engines

   Riccardo Tommasini, Emanuele Della Valle, Marco Balduini , and 1 more author

   In The Semantic Web. Latest Advances and New Domains - 13th International Conference, ESWC 2016, Heraklion, Crete, Greece, May 29 - June 2, 2016, Proceedings , May 2016
2. Towards Ontology-Based Event Processing

   Riccardo Tommasini, Pieter Bonte, Emanuele Della Valle , and 3 more authors

   In OWL: - Experiences and Directions - Reasoner Evaluation - 13th International Workshop, OWLED 2016, and 5th International Workshop, ORE 2016, Bologna, Italy, November 20, 2016, Revised Selected Papers , May 2016

2015

1. Efficient and Expressive Stream Reasoning with Object-Oriented Complex Event Processing

   Riccardo Tommasini

   In Proceedings of the ISWC 2015 Doctoral Consortium Co-located with the 14th International Semantic Web Conference (ISWC 2015), Bethlehem, Pennsylvania, USA, October 12th, 2015. , May 2015
2. Heaven Test Stand: Towards Comparative Research on RSP Engines

   Riccardo Tommasini, Emanuele Della Valle, Marco Balduini , and 1 more author

   In Joint Proceedings of the 1st Joint International Workshop on Semantic Sensor Networks and Terra Cognita (SSN-TC 2015) and the 4th International Workshop on Ordering and Reasoning (OrdRing 2015) co-located with the 14th International Semantic Web Conference (ISWC 2015), Bethlehem, Pennsylvania, United States, October 11th - and - 12th, 2015. , May 2015